When traveling on foot in remote locations such as during hiking, camping, military operations, or other, the size and weight of the equipment one is carrying is a very important issue. Devices used to purify water in these remote locations (where no electricity may be available) primarily fall into three categories: chemical disinfection (e.g., chlorine, iodine), adsorption (e.g., activated carbon, adsorptive resins), and filtration (e.g., membrane filters, ceramic or carbon filter blocks). A drawback of filtration devices used for this purpose is their relatively large size. The larger size is generally due to the fact that a pump mechanism is somehow attached to the filter so that one can generate sufficient pressure to force water across the filter as part of the purification process. A typical arrangement is one whereby a volume displacement type pump is in series with a filter device. The volume displacement pump is generally a piston type pump which includes a stationary barrel component and a moveable plunger component. Examples of these include First Need Delux, from General Ecology, Inc (Exton, Pa.), and SweetWater Purifier, from Mountain Safety Research, Inc. (Seattle, Wash.) Though the filter and pump mechanism can be semi-rigidly attached to one another, a problem with these designs is their large size is basically caused by having the filter and pump as two discrete elements. For example, the overall size (i.e. the volume the whole device occupies) is the sum of each component (i.e. it's the pump volume plus the filter volume). Upon examining the pump volume, one must use the whole barrel volume, regardless if the if the plunger component is fully inserted inside the barrel. This is because the area behind the plunger still takes up what would be considered storage space.
Thus, there is a perceived need for a compact fluid purification device with a manual pumping mechanism and which overcomes the above deficiencies.